• Food Science and Preservation
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• v.6 no.2
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• pp.179-183
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• 1999

This study were comparison the quality characteristics of winter Chinese cabbage and investigation the physicochemical properties during Kimchi fermentation. External characteristics of three cultivars winter Chinese cabbage were compared, total weight of "Manpung" cultivar showed the heaviest in Chinese cabbages, but edible portion weight of "Seolwang" cultivar showed the heaviest in Chinese cabbages. Kimchi made of winter Chinese cabbage were fermented at 5$^{\circ}C$ for 40 days, of which pH, acidity, free sugar and organic acid were measured. The hardness of "Manpung" cultivar continued highly during the Kimchi fermentation at 5$^{\circ}C$. The pH and total acid in Kimchi fermentation, of the "Manpung" cultivar changed more than those of others. At the initial stage of Kimchi fermentation the major organic acid was citric acid, but lactic acid and acetic acid were increased rapidly during fermentation of Kimchi. The major organic acid of Kimchi fermented for 30 days was lactic acid, and the lactic acid contents of Kimchi prepared with "Manpung" cultivar was 6,796.6$\mu\textrm{g}$/g account for 69.6% of total organic acid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.48-53
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• 1995

Changes in the contents of sugar, organic acid, free amino acid and uncleic acid-related compounds of leaf mustard-Kimchi during fermentation at 5~7$^{\circ}C$ were investigated. The leaf mustard-Kimchi was formulated with 4kg leaf mustard, 120g garlic, 80g ginger, 540ml salted anchovies, 1kg green onion, 200g red pepper powder, 200g ground red pepper, 60g whole sesame and 600ml glutinous rice paste. Changes in pH and acidity were relatively slow. Major free sugars were glucose(0.13%) and maltose(0.42%), and residual sugars(0.03-0.04%) were also detected after 32 days of fermentation. Major free amino acids containing more than 26.5mg% were proline, glutamic acid, alanine and histidine. Contents of total free amino acids increased from 244.8 to 397.2mg% by 24 days of fermentation. Of non-volatile organic acid, lactic acid was the most abundant(119.3mg%), and its content increased markedly after 10 days of fermentation. Other organic acids(below 53.1mg%) observed were malic, oxalic and citric acid. Contents of nucleic acid-related compounds were high in the order of hypoxanthine(22.8mg%), IMP(8.3mg%) and GMP(6.9mg%). Hypoxanthine content increased by 10 days(27.3mg%) and decreased thereafter, while the others decreased gradually during the overall period of fermentation.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.1-8
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• 2017

The production of high-value chemicals from natural resources as an alternative for petroleum-based products is currently expanding in parallel with biorefinery. The use of lignocellulosic biomass as raw material is promising to achieve economic and environmental sustainability. Filamentous fungi, particularly Aspergillus species, are already used industrially to produce organic acid as well as many enzymes. The production of lignocellulose-degrading enzymes opens the possibility for direct fungal fermentation towards organic acids such as itaconic acid (IA) and fumaric acid (FA). These acids have wide-range applications and potentially addressable markets as platform chemicals. However, current technologies for the production of these compounds are mostly based on submerged fermentation. This work showed the capacity of two Aspergillus species (A. terreus and A. oryzae) to yield both acids by solid-state fermentation and simultaneous saccharification and fermentation. FA was optimally produced at by A. oryzae in simultaneous saccharification and fermentation (0.54 mg/g wheat bran). The yield of 0.11 mg IA/g biomass by A. oryzae is the highest reported in the literature for simultaneous solid-state fermentation without sugar supplements.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.173-182
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• 2019

To produce a high-quality Kimchi product, molten salt was used for the Kimchi. Changes in the physiochemical properties and functional compounds were analyzed during fermentation. The salinity of bay salt Kimchi was higher than that of the molten salt Kimchi. The fermentation speed of the lactic acid bacteria in the molten salt Kimchi was significantly faster. To evaluate the effects of the salts on the changes in the functional compounds during fermentation, the antioxidant activity, total phenolic compounds (TPC), flavonols, phenolic acids, and glucosinolates in Chinese cabbage were analyzed. In the first 9 days, antioxidants were decreased during this fermentation period and then, increased after that. TPC was slightly increased for all the conditions after 40 days fermentation. Kaempferol was a major flavonol but had a relatively larger decrease in the molten salt Kimchi than in the bay salt samples. Phenolic acid did not show any significant difference among the samples. The glucosinolate contents were significantly decreased in all the conditions of Kimchi during the fermentation period. Consequently, the molten salt greatly affected the fermentation speed of Kimchi and the total characteristics of the Kimchi lactic acid bacteria. Although the functional compounds of Chinese cabbage were decreased during the fermentation of Kimchi, this decrease did not profoundly deteriorate the food quality. Therefore, high-quality Kimchi with enhanced bioactivity will be available if appropriate Chinese cabbages that have enhanced functional compounds are used.

• Food Science and Preservation
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• v.7 no.1
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• pp.89-93
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• 2000

The study was conducted to investigate the characteristics of peach vinegar by parallel-complex fermentations. The vinegars prepared by using Changbnag-Chosang and Yumung peach cultivars added with 7, 10, and 13% sugaring concentrations were examined. The rate of increase in alcohol degree and titratable acidity, and that of decrease in soluble solids showed higher at Yumyung peach than at Changbang-chosang. Alcohol and acetic acid fermentation by paralle-complex fermentation were performed better in Yumyung peach than Changbang -chosang. but the fermentation of Yumyung showed active alcohol fermentation in the early stage, and active acetic acetic acid fermentation in the late stage. Quality of the vinegar prepared with Yumyung peach was better than that of Changbang-chosang, which were evaluated by acetic acid contents , peach taste and odor in the vinegar, and overall taste. The fermentation was accelerated with an increase in sugaring , concentrating but overall taste was best in 10 % sugaring.

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.671-677
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• 2013

The objective of this study was to examine the levels of free amino acids and identify the correlation between ${\gamma}$-aminobutyric acid (GABA)and L-glutamic acid contents in Kimchi during fermentation. During 2 weeks of fermentation, the acidity of Kinchi increased, i.e., the pH level decreased from 5.24 to 4.40. The content of amino acids determined using HPLC differed significantly (p < 0.05) during 7 weeks of fermentation. Over the 7 weeks of fermentation, the content of most free amino acids increased in the order L-valine > L-glutamic acid > L-glycine, except L-methionine decreased. Initially, the GABA content was found to be $72.43{\mu}M/100g$ fresh weight (fw), and it increased to $229.06{\mu}M/100g$ fw after 7 weeks. This rapid increase in the GABA content in the initial stage is considered to be due to L-glutamic acid. However, during the period of 0~7 weeks, no correlations were found between the L-glutamic acid and GABA contents.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.377-389
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• 2013

Gamma-amino butyric acid (GABA) is a kind of pharmacological and biological component and its application is wide and useful in Korea specially, becoming aging society in the near feature. GABA is request special dose for the purposed biological effect but the production of concentrated GABA is very difficult due to low concentration of glutamic acid existed in the fermentation broth. To increase GABA concentrate using fermentation technology, high content of glutamic acid is required. For this reason, various strains which have the glutamic acid decarboxylase (GAD) and can convert glutamic acid to GABA, were isolated from various fermented foods. Most of GABA producing strains are lactic acid bacteria isolated from kimchi, especially added monosodium glutamate (MSG) as a taste enhancer. Optimizing the formulation of culture media and the culture condition, GABA conversion yield and amounts were increased. Finally GABA concentration of fermentation broth in batch or fed batch fermentation reached 660 mM or 1000 mM, respectively. Furthermore formulation of culture media for GABA production developed commercially. Many studies about GABA-rich product have been continued, so GABA-rich kimchi, cheese, yogurt, black raspberry juice and tomato juices has been also developed. In Korea many biological effects of GABA are evaluated recently and GABA will be expected to be used in multipurpose.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.869-877
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• 2017

Lactic acid bacteria (LAB) are used as fermentation starters in vegetable and dairy products and influence the pH and flavors of foods. For many centuries, LAB have been used to manufacture fermented foods; therefore, they are generally regarded as safe. LAB produce various substances, such as lactic acid, ${\beta}$-glucosidase, and ${\beta}$-galactosidase, making them useful as fermentation starters. Existing functional substances have been assessed as fermentation substrates for better component bioavailability or other functions. Representative materials that were bioconverted using LAB have been reported and include minor ginsenosides, ${\gamma}$-aminobutyric acid, equol, aglycones, bioactive isoflavones, genistein, and daidzein, among others. Fermentation mainly involves polyphenol and polysaccharide substrates and is conducted using bacterial strains such as Streptococcus thermophilus, Lactobacillus plantarum, and Bifidobacterium sp. In this review, we summarize recent studies of bioconversion using LAB and discuss future directions for this field.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1130-1136
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• 2006

This work elucidates the effects of pretreatment of the sewage sludge from wastewater treatment plant by microwave irradiation on elutriated acid fermentation. These experiments typically fell into two process; pretreatment as microwave irradiation and elutriated acid fermentation for hydrolysis and acidification as main process of primary sludge. The results of maximum solubilization rate of B, D primary and secondary sludge were 0.042, 0.086 and 0.15 gSCODprod./gICODin and the optimum irradiation time of microwave on 2,450 MHz and 900 W were 5 min. for primary sludge and 7 min. for secondary sludge. From batch tests on elutriated acid fermentation that was used the pretreated primary sludge as microwave, the optimum pH and HRT (hydraulic retention time) were 7 and 5 days at $35^{\circ}C$ condition.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.353-358
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• 1999

We produced the apple vinegar with only apple fruits, no adding sugar and others through two stages fermentation(alcohol fermentation and acetic acid fermentation). At the first stage, apple wine contained 5% alcohol was produced at the 5th day. And through the second stage, acetic acid fer mentation, apple vinegars of which total acidity is 5.88% were produced. In comparision with com mercial vinegars for physicochemical quality, it was the lowest in total acidity. But contents of oxalic, tartaric, malic, citric, succinic acid in it were higher than other vinegars. Especially the content of malic acid in it was higher 5 times than other vinegars. Malic acid was known that it was abundant in apple fruits. Also the contents of free amino acids were distinctly high such as 21.97mg% in two stages fermented apple vingars. Potassium content in it was higher 4 times than other vinegars. So it was supposed that two stages fermented vinegar had much higher quality than commercial vinegars.